As you sleep, antibodies from your hair gradually impregnate the memory foam.
Over time, they are assimilated into the micro-pores of the foam structure, and the pillow learns who you are.

If a stranger then tries to use your pillow, natural enzymes are released from the patented nano-capsules, and they gradually dissolve the hair, skin, flesh and eventually the entire head of the interloper.

When you return the item, they ask for your reason of return. They then give back your money. Nothing more, nothing less.
You have to maintain your membership over this time for this generous warranty. (I agree heartily with the scumbag comment).